The age and stratigraphic division of the Wufeng Shale has buried an unresolved issue in the Chinese geological community for a long time since its birth. A paper "On the Wufeng Shale" was published in 1954 (Mu, 1954) with a reliable conclusion obtained that the Wufeng Formation belongs to the Upper Ordovician. There are too much insignificant species or subspecies and many wrong identification in the monograph "Upper Ordovician Graptolites...